The Tourniquet Manual: Principles and Practice - part 8 pot

This page intentionally left blank Chapter 6 The Tourniquet Used for Anaesthesia This page intentionally left blank T HIS CHAPTER DISCUSSES intravenous regional anaesthesia and digital tourniquets. 6.1 Intravenous Regional Anaesthesia In 1908, August Karl Gustav Bier (1851–1949; Figure 6.1), first assistant to Johann Frederick August von Esmarch at the time, devised an effective method of bringing about complete anaesthesia and motor paralysis of a limb. J. Leonard Corning had, in 1895, published the results of experiments of the effects of how the use of a tourniquet after subcutaneous injection of five minims of cocaine into the forearm prolonged and intensified the anaesthesia. 1 If the injection was carried out after exsanguination and compression, there was little diffusion of the anaesthetic and a reduction in the number of nerve filaments exposed to the influence of the solu- tion. If the drug was injected a few moments before exsanguination and the 79 Figure 6.1 August Bier in his youth. Reprinted with permission from the Wellcome Library, London. application of the tourniquet, a sufficient saturation of the tissue was achieved to expose a large number of the nerve filaments to the solution. Corning suggested that this technique was applicable to surgery of the extremities. Bier, a pioneer of spinal anaesthesia, established this technique. It was cumbersome by modern stan- dards. He injected a solution of procaine into a subcutaneous vein on a section of the forearm that was visible between two constricting bands and that had been rendered bloodless by an Esmarch bandage. A surgical cut-down was required to locate the vein. The injected solution permeated through the exposed section of the limb very quickly and produced what Bier called “direct vein anaesthesia” in 5–15 minutes. The anaesthesia lasted for as long as the upper constricting band was left in place. After its removal, sensation returned in a few minutes. The development of techniques of regional anaesthesia followed that of drugs that could produce local anaesthesia. Gaedicke isolated cocaine in 1855. It was purified and named by Nieman in 1860 and first used as a local anaesthetic by Koller in 1864. Cocaine was used for infiltration anaesthesia and major nerve blocks, which were popularised by both Halsted and Crile. The systemic toxicity of cocaine limited its use as a local anaesthetic. The practice of regional blocks was enhanced greatly when procaine was synthesised by Einhorn in 1904. Braun went on to establish the use of procaine for regional anaesthesia. 2 The technique did not become used widely, despite Bier’s reports of its use with Esmarch bandages in 134 patients, including ten amputations, 37 resections, 12 sutures of bones, ten tendon transfers, two Dupuytren’s contractures, and seven cases of extirpation of varicose veins. Bier first conceived the possibility of the method when he injected a solution of indigo carmine into the veins of an ampu- tated limb. 3 He found that there was widespread diffusion of the dye. He considered that the anaesthesia was of two types: direct and indirect. Direct anaesthesia was due to infiltration of the fluid into the tissues and around the nerve filaments and occurred rapidly. A little later, because of blocking of the larger nerve trunks passing through the exsanguinated region, further anaesthesia occurred distally (indirect anaesthesia) Today, the mechanism remains open to dispute and a combination of theories may best explain the effects. Despite Bier’s report of none of 134 patients showing any ill effects, his technique appears to have been forgotten until 1963, when it was reintroduced by Holmes. 4 The technique was used on a limited scale but did not gain widespread popularity. There are a number of reasons for this 5 : the technique was cumbersome, requiring wrapping and unwrapping of Esmarch bandages in a precise manner; special equip- ment was required; and an operative procedure (cut-down) was used. It was Morrison in 1931 who first suggested a venepuncture and made the method more practi- cable. 6 Although Holmes used lignocaine, 0.5% prilocaine is now regarded as the drug of choice. 7 Only the 0.5% solution should be used, and the recommended dose is 3–4 mg/kg. The method has now been refined. An intravenous cannula should be inserted into each hand. The limb should be exsanguinated before the tourniquet is inflated. This can be done by elevation and careful application of an Esmarch bandage, taking care not to dislodge the intravenous needle; alternatively, a pneumatic splint can 1111 2 3 4 5 611 7 8 9 1011 11 2 3111 4 5 6 7 8 9 2011 1 1 2 3 4 5 6 7 8 9 3011 1 1 2 3 4 5 6 7 8 9 4011 1 211 80 The Tourniquet Manual ➀➁➂➃➄➏➆ be used. 8 With the tourniquet inflated, the local anaesthetic agent is injected slowly. A double cuff can be used proximally; once anaesthesia has been achieved, the upper cuff can be released after the lower one has been inflated. It must be remem- bered that a significantly higher pressure is necessary (systolic plus 100 mm Hg) for the double cuff because of its narrow width, although in this way the pain from the tourniquet cuff can be reduced. There is no doubt that a single cuff is easier, less complicated, and safer to use (Figure 6.2). The effect of exsanguination is not completely clear. The most impor- tant reason for exsanguination is to collapse the vascular compartment of the limb, i.e. to empty the blood from the limb and allow the space to be taken up by local anaesthetic. Injection of the anaesthetic solution into a full vascular compartment will impair complete distribution through the distal part of the limb. With the tourni- quet inflated, the vascular compartment is a closed space, and relative collapse of the compartment is necessary to be able to accommodate the injection of the solu- tion. The blotchy areas of erythema that appear as the anaesthetic is injected result from residual blood forced into the skin. The appearance of these areas indicates wide distribution of the anaesthetic. They appear regardless of the method used for exsanguination and do not signify that one is to expect poor analgesia. Intravenous regional anaesthesia is a potentially dangerous technique because of the possibility of injection into the systemic circulation. Precautions are required in all cases. All the equipment used must be checked for leaks. The patient must be pre- pared and starved. Drugs for resuscitation are required. Full monitoring of the cardio- vascular system must be available. Rapid injection of local anaesthetic should be avoided, since it may force fluid past the tourniquet. The needle should be as far dis- tal as possible, and not in the antecubital fossa. Caution is needed for hypertensive and arteriosclerotic patients, as the tourniquet may not completely compress the main vessels in the arm. This technique should not be performed by the surgeon alone. An anaesthetist is required to ensure adequate supervision of the patient. Analgesia is usually complete within four to six minutes, continuing for up to 90 minutes. However, procedures lasting for more than half an hour become uncomfortable because of pain from the tourniquet. Early loss of cutaneous sensation to pinprick is a good guide to the 81 ➀➁➂➃➄➏➆ The Tourniquet Used for Anaesthesia Figure 6.2 Diagram of a single cuff and intravenous needle after exsanguina- tion. The intravenous needle is as far distal as possible. This is the simplest and safest technique. effectiveness of the block. As muscle relaxation occurs, the limb should feel heavy to the patient. This method is useful for distal fractures in the upper limb, ganglions and decom- pression of the median nerve. It is not used commonly for the lower limb, mainly because of the volume of local anaesthetic agent required. After completion of the operation, the cuff should be deflated gradually in a step- wise manner to avoid a bolus injection of local anaesthetic. Sensation and motor power return after several minutes. The minimum tourniquet time suggested is 20 minutes to allow adequate diffusion into the ischaemic region. The adverse effects of intravenous regional anaesthesia are due to accidental, sudden deflation of the cuff and deflation too soon after the injection of local anaesthetic. Sudden release results in a bolus of any unfixed local anaesthetic. Underinflation of the cuff will allow leakage to occur into the systemic circulation. In 1982, in an editorial in the British Medical Journal, Margaret Heath noted that since 1979 the Scientific and Technical Branch of the Department of Health and Social Security in London had been informed of five deaths resulting directly from the use of intravenous regional analgesia. 9 The drug used was bupivacaine. In three of the most recent cases, it was found that the equipment was in good order but the cuff had been deflated when it should not have been. The likelihood of direct intravenous injection during routine procedures has been underestimated. The effects of such a bolus are likely to be worse in frightened patients, as circulatory catecholamines will ensure that the maximum amount of the cardiac output reaches the brain and heart, which are the main target organs for toxicity. The recognition and treatment of toxic reactions are crucial. There is also the problem of individual low thresholds. Major side effects of using prilocaine have not been recorded in Britain. Prilocaine is the safest local anaesthetic for intravenous local anaesthesia. It is no longer available in North America in a form suitable for intravenous injection because of concern about methaemoglobinaemia, although this does not occur in the dosages used; lidocaine is commonly used in North America instead. 10 6.2 Digital Tourniquets When performing a minor procedure on a single digit, finger or toe, it is convenient to apply a tourniquet at the base of the digit rather than use a proximal tourniquet for the whole limb. A variety of techniques have been described. A common method is to wrap a soft rubber catheter or Penrose drain around the base of the finger or toe under tension and keep it in place with an artery forceps. Salem suggested a method that is now used commonly 11 : he cut off the finger of a disposable glove, removed the tip, stretched and applied it to the digit for operation, and rolled it proximally to form a ring at the base of the digit. This provides a satisfactory blood- less field. The ring can readily be cut and removed when the operation has been 1111 2 3 4 5 611 7 8 9 1011 11 2 3111 4 5 6 7 8 9 2011 1 1 2 3 4 5 6 7 8 9 3011 1 1 2 3 4 5 6 7 8 9 4011 1 211 82 The Tourniquet Manual ➀➁➂➃➄➏➆ 83 ➀➁➂➃➄➏➆ The Tourniquet Used for Anaesthesia Figure 6.3 Salem’s method of applying a digital tourniquet: (a) A finger from a rubber glove is rolled proximally. Figure 6.3 (b) The tourniquet is grasped in an artery clip. completed. A recent modification suggests that the tourniquet should be gripped by an artery clip, with the handle pointing proximally. 12 The rubber ring is cut above the clip with scissors. This ensures that when the tourniquet is released, the danger of the tourniquet remaining in place is avoided (Figure 6.3). A study of the pres- sures involved using a miniature pressure transducer and digital strain indicator has shown that the Penrose drain generated highly variable pressure, often greater than 500 mg Hg. 13 In contrast, the rolled finger from a glove, in addition to producing exsanguination, uniformly generated pressures of less than 500 mg Hg, which is below the threshold required to produce nerve damage. The main danger is that a digital tourniquet may be forgotten, covered with a dressing, and left to cause gangrene in the anaesthetised finger or toe (Figure 6.4). A rare case of ischaemia of the distal half of a finger has been reported, which recov- ered with treatment by intravenous infusion of low-molecular-weight dextrose, intravenous dipyridamole, and alcohol. The finger was packed in ice and the arm was warmed. The report was from a unit using a tourniquet for at least 1000 oper- ations a year, and this was the first complication observed. 14 6.3 Regional Sympathetic Blockade For patients suffering complex regional pain syndrome (CRPS) type I (also known as reflex sympathetic dystrophy), a technique similar to intravenous regional anaes- thesia has been used with a tourniquet in place. 15 A solution of 20 mg (for the upper limb) or 30 mg (for the leg) of guanethidine in normal saline is injected. The cuff is kept inflated for 15 minutes. This produces complete sympathetic blockade 1111 2 3 4 5 611 7 8 9 1011 11 2 3111 4 5 6 7 8 9 2011 1 1 2 3 4 5 6 7 8 9 3011 1 1 2 3 4 5 6 7 8 9 4011 1 211 84 The Tourniquet Manual ➀➁➂➃➄➏➆ Figure 6.3 (c) The rubber ring is cut above the clip. Reproduced with permission from Elsevier Science from Smith, IM, Austin, OB, Knight, SL (2002). A simple and failsafe method for digital tourniquet. Journal of Hand Surgery 27B; 363–364. for up to four days, reducing the pain in the affected limb and allowing active physiotherapy. Although this technique has been considered accepted practice for many years, recent work has shown that guanethidine offers no significant advan- tage in analgesia over a normal saline placebo block in the treatment of early CRPS type 1 of the hand after a fracture of the distal radius. 16 Guanethidine does not improve the outcome of this condition, and it may delay the resolution of vaso- motor instability when compared with placebo. 85 ➀➁➂➃➄➏➆ The Tourniquet Used for Anaesthesia Figure 6.4 Gangrenous thumb after a digital tourniquet had been left in place for too long. Reproduced with permission from Elsevier Science from Smith, IM, Austin, OB, Knight, SL (2002). A simple and failsafe method for digital tourni- quet. Journal of Hand Surgery 27B; 363–364. [...]... anaesthesia Anaesthesia and Analgesia 85 : 85 3 86 3 11 Salem, MZA (1973) Simple finger tourniquet British Medical Journal 2: 779 12 Smith, IM, Austin, OB, Knight, SL (2002) A simple and fail safe method for digital tourniquet Journal of Hand Surgery 27B: 363–364 13 Hixson, FP, Shafiroff, BB, Werner, FW, Palmer, AK (1 986 ) Digital tourniquet a pressure study with relevance Journal of Hand Surgery 11A: 86 5 86 7.. .The Tourniquet Manual 1111 2 3 4 5 611 7 8 9 1011 11 2 3111 4 5 6 7 8 9 2011 1 1 2 3 4 5 6 7 8 9 3011 1 1 2 3 4 5 6 7 8 9 4011 1 211 ➀➁➂➃➄➏➆ References 1 Corning, JL ( 189 5) Anaesthetic effects of the hydrochlorate of cocaine when subcutaneously injected New York Medical Journal 42; 317–319 2 Hilgenhurst, G (1990) The Bier block after eighty years Regional Anaesthesia 15: 2–5 3 Adams,... (1 982 ) Ischaemia after use of a finger tourniquet British Medical Journal 284 : 1162–1163 15 Hannington-Kiff, JG (1974) Intravenous regional sympathetic block with guanethidine Lancet i: 1019–1020 16 Livingstone, JA, Atkins, RM (2002) Intravenous regional blockade in the treatment of post-traumatic complex regional pain syndrome type 1 (algodystrophy) of the hand Journal of Bone and Joint Surgery 84 B:... Anaesthesia New York: Paul B Hoeber, p 111 4 Holmes, CM (1963) Intravenous regional anaesthesia Lancet 1: 245–247 5 Colbern, EC (1970) The Bier block for intravenous regional anaesthesia Technique and literature review Anaesthesia and Analgesia 49: 935–940 6 Morrison, JL (1931) Intravenous local anaesthesia British Journal of Surgery 18: 641–647 7 Bader, AM, Concepion, M, Hurley, RJ, Arthur, GR (19 98) ... Hurley, RJ, Arthur, GR (19 98) Comparison of lidocaine and prilocaine for intravenous regional anaesthesia Anesthesiology 69: 409–412 8 Winnie, AP, Ramamurthy, S ((1970.) Pneumatic exsanguination for intravenous regional anaesthesia Anesthesiology 33: 664–5 9 Heath, M (1 982 ) Deaths after intravenous regional anaesthesia British Medical Journal 285 : 913–914 10 Henderson, CL,Warriner, CB, McEwen, JA,... Atkins, RM (2002) Intravenous regional blockade in the treatment of post-traumatic complex regional pain syndrome type 1 (algodystrophy) of the hand Journal of Bone and Joint Surgery 84 B: 380 – 386 86 Chapter 7 Technology and Practice . can 1111 2 3 4 5 611 7 8 9 1011 11 2 3111 4 5 6 7 8 9 2011 1 1 2 3 4 5 6 7 8 9 3011 1 1 2 3 4 5 6 7 8 9 4011 1 211 80 The Tourniquet Manual ➀➁➂➃➄➏➆ be used. 8 With the tourniquet inflated, the local anaesthetic. With the tourni- quet inflated, the vascular compartment is a closed space, and relative collapse of the compartment is necessary to be able to accommodate the injection of the solu- tion. The. cut and removed when the operation has been 1111 2 3 4 5 611 7 8 9 1011 11 2 3111 4 5 6 7 8 9 2011 1 1 2 3 4 5 6 7 8 9 3011 1 1 2 3 4 5 6 7 8 9 4011 1 211 82 The Tourniquet Manual ➀➁➂➃➄➏➆ 83 ➀➁➂➃➄➏➆